Piston-driven firearms as understood by those skilled in the art typically use an operating piston that reciprocates at some distance from a firearm barrel. An AK-47, for example, utilizes an operating piston that reciprocates above the firearm barrel. While the use of an offset operating piston can help provide reliability as compared to a direct-impingement operating system, for example, offset pistons can make semi- and especially fully-automatic firearms difficult to control because the offset piston's reciprocating mass creates a torque about the barrel. Accordingly, there is a need in the art for a firearm operating system that can provide the reliability advantages of a conventional offset piston while minimizing or even eliminating the barrel torque caused by an offset piston. Such a firearm operating system could provide numerous benefits for auto-loading firearms and would be especially useful for auto-loading rifles, carbines, and personal-defense weapons.